The invention relates to a ruggedly constructed spectacle frame for use during periods of extreme physical activity, particularly by military personnel during combat operations, and which can be used under protective face masks and headgear.
The invention also relates to an eyeglass frame which can be used by children and infants, as well as by persons participating in sports and occupations requiring the use of face masks, headgear and industrial eye protective devices.
The invention further relates to a spectacle frame comprising in combination rim means defining a pair of spaced side-by-side viewing windows and having a recessed contoured bridge therebetween, a temple yoke support means pivotly mounted to said rim above and below said viewing windows by means of temple pivot posts on said rim means and an adjustable strap having a connector means at the ends thereof for slidable connection to said temple yoke to allow varying angles of tilt of the frame relative to the face.
The invention also relates to a spectacle frame which does not restrict peripheral vision and freely conforms to the head over the temple to eliminate the large angle from the temple to the ear and thus allow use with protective gas masks, face masks and other headgear.
The prior art spectacle frame has remained substantially the same during the past two hundred years, namely consisting of a frame containing two lens inserts and two temple side arm or ear pieces which are attached to the frame by means of a metal hinge and pin or screw. These prior art spectacles require careful fitting to the face of the user by trained personnel and are subject to be easily damaged, misaligned or broken, particularly during physical activity. Elastic straps attached to the ends of the temple side arms have been used to hold spectacles on the user's face, but this method has been only partially successful in maintaining the eyeglasses in their proper position during extreme physical activity. Prior frames have also caused discomfort on the nose, eyelashes touching the lenses and lens fogging.
The long felt need for a ruggedly constructed spectacle frame has been particularly acute in the military where a large number of users have to operate under conditions of extreme activity and where the loss in time, expense and individual effectiveness due to the need for individual fitting of eyeglasses is of staggering proportions. Added to these problems is the need for providing tight fitting protective gas masks and other headgear which interfere with standard eyeglass frames. In particular, conventional eyeglass frames have a large angle from the temple to the ear and obstruct peripheral vision. When used under a mask, the prominent temple corners hit the mask, causing extreme discomfort due to pressure of the frame against the nose, and leakage of the mask at the sides of the head.
To overcome this problem of eyeglass use under protective masks, the military has had to design a number of optical "inserts" for difficult mask configuration which have to be mounted into the particular masks. These inserts require skilled fitting to the needs of the user and are not as a rule interchangeable between different mask designs. The quality of vision provided with these optical inserts is not good and the size of insert which can be accommodated in the mask has proven to be inadequate as well as uncomfortable for the wearer. The above disadvantages, coupled with the delays in obtaining and adjusting the optical inserts, have resulted in only limited use of these inserts for those personnel having the highest degree of visual impairment.